An apparatus developed for measurement of dynamic friction coefficient is presented. The dynamic friction coefficient of paddy grains was determined and studied in three varieties (Alikazemy, Hashemi and Khazar), at two levels of moisture content (12 and 23% w.b.), three levels of peripheral speed (0.5, 3.5 and 6.5 cm s-1) and on three contact surfaces (black, mild and galvanized sheets). The experiments were arranged as a split-split plot fitted into randomized complete block. The results of variance analysis revealed that the effects of grain moisture content, variety, contact surface, peripheral speed and their interactions were significant (p<0.01) on dynamic friction coefficient. With increase in the moisture content of grain and peripheral speed of disc, dynamic friction coefficient increased. Among the contact surfaces, the highest and lowest values of dynamic friction coefficient were 0.567 and 0.314 and belonged to the black and galvanized sheets, respectively. Also, among the varieties, Alikazemi and Khazar varieties had the maximum and minimum mean values, respectively.
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机译：提出了一种用于测量动摩擦系数的设备。测定并研究了三个品种（Alikazemy，Hashemi和Khazar）在两个水平的水分含量（12％和23％wb），三个水平的圆周速度（0.5、3.5和6.5 cm s-下）下的稻谷动摩擦系数。 1）并在三个接触面上（黑色，中性和镀锌板）。实验被安排为适合整个随机区组的分割图。方差分析的结果表明，谷物含水量，品种，接触表面，圆周速度及其相互作用对动摩擦系数的影响显着（p <0.01）。随着谷物水分含量和圆盘圆周速度的增加，动摩擦系数增加。在接触表面中，动摩擦系数的最大值和最小值分别为0.567和0.314，分别属于黑色和镀锌板。同样，在品种中，Alikazemi和Khazar品种分别具有最大和最小平均值。
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